Fluid-operated clamping device with mechanical advantage and delayed release action



Dec. 22, 1953 J. VERDERBER ELUID-CPEEATED CLANPINC DEVICE wITH MECHANICAL ADVANTAGE AND DELAYED RELEASE ACTION 4 Sheets-Sheet 1 Filed Sept. 9, 1952 si? lli INVENTR. JOSEPH VERDERBER BY A MM @Mm ATTORNEYS Dec. 22, 1953 J, VERDI-:REER 2,663,151

FLUID-OPERAIED CEAMPING DEVICE WITH MECHANICAL ADVANTAGE AND DELAYED RELEASE ACTION Filed Sept. 9, 1952 I 4 Sheets-Sheet 2 L I I 52 /58 f f is `1 /ll l \"7 y e5 VIII/Illy s? /y n 54 72 ,l 64b IO 73 j J I I .o f/// f W IN VEN TOR. JOSEPH VERDERBER ELI/Wauw ATTORNEYS Dec. 22, 1953 VERDERBER 2,663,151

J. FLUID-OPERATED CLAMPING DEVICE WITH MECHANICAL ADVANTAGE AND DELAYED RELEASE ACTION 4 sheets-sheet 5 Filed Sept. 9, 1952 36 |5 INVENTOR. 35 43 33 JOSEPH VERDERBER BVM/MW ATTORNEYS Dec. 22, 1953 J. VERDERBER 2,663,151

' FLUIDfOPERATED CLAMPING DEVICE WITH MECHANICAL ADVANTAGE AND DELAYED RELEASE ACTION Filed Sept. 9, 1952 4 Sheets-Sheet 4 45 43 //JNVENTOR.

s P` R BY Jo E H 4vs DERBER ATTORNEYS Patented Dec. 22, 1953 UNITE!)y STATES PATENT OFFICE FLUID-OPERATED CLA MECHANICAL ADV RELEASE ACTION MPING DEVICE WITH ANTAGE AND DELAYED Joseph Verderben cleveland, ohio Application september 9, 1952, seria1 No.aos,5so

` (c1. so-97) 7 Claims.

The present application relates generally to pressed air is likewise utilized to move piston- 2 actuated camming rods or wedges into and out yof camming engagement with elements of the clamping bar.

In my copending patent application Serial No. 302,331 filed August 2, 1952, andentitled Fluid- Operated Clamping Device With Mechanical Advantage I have disclosed a device in which compressed uid is utilized to elevate a clamping bar which has positive enter-engagement with piston-actuated camming rods or wedgeswhich are controlled by compressed air.` The retraction of the wedges induces the retraction of the clamping bar, mechanically. A

In both of the foregoing disclosures, each of the camming wedges was integrated with an independent piston, and in the operation of the device the fluid pressures were exerted simultaneously Acin the wedges and the clamping bar so that retraction of the device was accomplished by 'a concurrent withdrawal of the clamping bar and the wedges. y

It is the primary object of my invention to provide a clamping device yof the character described in whichV a single piston'is utilizedto motivate a plurality of camming wedges, thereby effecting lsubstantial economies in manufacture as well as improved performance. 1 l Y Another object of my invention is to'provide a clamping device of the character described in which the member connecting the piston to the camming wedges is so v'constructed and arranged will be apparent urneiheeorsepf. the v i.ollvingy description,v

that it will yield to slight-inequalities inthecon- In the accompanying drawings, forming a part of the specification, and in whichhke numerals are employedto designate like parts throughout the same,

' Fig. 1 is a top plan View of a clamping device embodying the features of my invention.

Fig. 2 is a cross-sectional view of the device taken on line Z-I-Zof Fig. 1 and showing details of the camming wedges.

Fig. 3 is a cross-sectional view taken v on line I 3 -3 of Fig. land showing detailsof the clamping bar piston and the wedge-.a9tuatingj piston.

Fig. 4 is a fragmentary cross-sectional view taken on line 4 4 of Fig. 1 and disclosing certain of the uid passage-ways.

Fig. 5 is a fragmentary cross-sectional'v view taken on line 5,-5 of Fig. 1 and showing another iluid passageway.

Fig. Gis a cross-sectional view'taken on line 6-6 of Fig. 2, a portion thereof being broken away to show the securement of the connecting bar.

Fig. 'iis a top plan view of a modified form of the invention, and

Fig.. 8 is a .cross-sectional view taken on line s-sofrigm Referring moreparticularly to Figs. 1 to 6,'

inclusive, of the drawings, the clamping device or jig comprises a base I0, which maybe a casting, Y

and which is of generally rectangular form. Mounted in the ,four corners of the base are upstanding posts I I to which is secured a top-plate I 2 against which the work-piece is clamped by the-mechanism to be described,

Projecting-vertically upwardly 'from the'base IIJ is a cylindrical embossment I3 having a longitudinal bore I4 extending completely therethrough. The borek I4 is counterbored as at I5 for a purpose to be described.

Slidably mounted in the bore I4 ofthe embossment I3 is a hollow cylindrical clamping bar I6 having an upper'closed'end I1 whichl forms -an interior face or surface I8. f

The lower open end` of the clamping bar IGC-is "threaded interiorly thereof as at, I 9 and has threadedly `secured thereto a plug '.20' having spaced spanner openings'2l provided therein fr ease'of assembly. The` 'plug `20th`us seals the open end of the clamping' bar` I6 to define acavity or air chamber`23 as willy appear more-fully here-A inafter.

lDislaosecl ,within the cavity;` isha "stationay,

divider 24 whichis substantially in the form ofw ra pisionfhe'eii harinexiellr spaced Pisten rings 26 mounted thereon which, having a wiping engagement with the wall of the cavity, serve to prevent the escape of air. The piston 25 has an integral rod or stem 21 which depends therefrom and extends through the plug 2d. The plug 2@ has an annular recess 28 therein, in which is secured an oil seal 29 which embraces the stern 21.

The stem 21 terminates in an extension 30 of reduced diameter thereby forming a circumferential shoulder 3i. The portion 36 of the stem eirtends through a bore 252 of a cap 33 which is mounted in the counterbore i and secured yto the base iii by means of screws 3:1. Anut 35 is threadedly secured to the portion 3@ of the stern and serves to maintain the shoulder 3i in abut ment with the cap 33.

The divider M has an axial closed-end 'bore 35 which starts a short distance above the end of the extension 3S. The bore 3e is countern bored as at 31, which counterbore extends through piston head 25 and stem 21 Vto a point a short distance above the end of bore 36, thereby forming a shoulder 38. A tube 39, having an internal diameter equal to that of bore 36 and having an external diameter of less than that of bore 31, is axially disposed within the bore 3l and secured against the shoulder 33 by means of two hollow set screws di! which are threadedly secured in the bore t? and engage and center the uper end of tube (it. The upper screwed serves as a locking screw andboth screws act as extensions of thebore 36.

The bore of the tube 39 thus provides an extension of the bore :iii of the'stem 21, which bore communicates with the upper portion A of the air chamber 23. rEhe tubeilil also defines an annular passageway 4| in the 'stem 21, which passageway communicates with the lower portion l?.l of the chamber through a diametrical opening 42 which is provided in the stem 21.

The cap 33, which fits snugly on the extension 3B of the stem, has two channels 43 and it formed therein. The channel it extends downward lfrom an annular face t5 of the cap '-33 and then extends angularly upwardly to the bore ofthe cap where it communicates with a radial opening'll' in the extension all which leads to the,

passageway M in bore A31. The channel 'ed is spaced circumferentially from the channel ce and runs downwardly from the face l5 and then radially to the bore 32 where-it communicates with a radial opening'di which leads to the bore 3S.

The base Iii is provided with openings 4S and 43 deiining'vertical channels which are in registry with the passageways d3 and M, respectively. Angular alignment of channels 43 and 4A. with the radial openings it and 41, respectively, is ef-V fected by means of a radial key on extension 3S which engages a lreyway 5| inthe 'cap y33'.

The above described arrangement of parts is fully disclosed and claimed in my copending application Serial No. 162,557 .filed May `17, 1950, entitled Fluid-Operated Clamping Device with Lubricant Atomizing Means.

The base lc is provided with an embossment in the form of cylinder block 52 having a central horizontally extending bore 53 and to either side thereof smaller bores 54.

The bore 53 denes V'a cylinder in which is mounted a piston 55 having sealing rings 5E which have wiping engagement with the wall of the cylinder. The piston has an integral rod or stem 51 which projects through a cylinder head 58 and into a hollow dust cover 59. The head 58 and recess. A tie bar or rocker bar @5, which is of a width slightly less then the depth of the recess 63, is-adapted to be received in the recesses and is pivotally secured to the rods Eil' and Gi by means oa pin 53 which is pressed into the apertures-@fisc as to traverse the bar d5 through apertures provided therein. It will be noted that this arrangementof the parts has the effect of causing the rods El to move in response to movement of piston rod 51 astransmitted through the rocker bari. It will also be noted that a clearance space 61 is provided between the bar 55 and the bottom of each recess 53. This space permits the bar 65 to have a limitedpivotal movement with respect to the axis of each of the pins 66 and thus provides a flexible structure which can yield to `slightl inequalities of movement ofthe rods 51'and 6l.

Each of the camming rods Si is adapted to engage a guide rod '68 which is `slidably mounted in a vertically'extending bore .t9 in the embossmentii. VThe guiderods 63 are secured at their upper ends' to aclamping block 1l which is ,driedly secured 'tothe clamping bar i6 for movement therewith.

The means for actuating'the clamping device consists of `fluid under pressure, such as come pressed air, the flow of which is controlled by a three-position valve 10 of the type disclosed in my aforesaid `copending application Serial No. 162,557. The lvalveis mounted on the is and is inregistrywith each of two horizontally extending channels 12 and 1.3 which are provided in the base I0.

As best seen in Figs. l Vand 4, the channel i2 communicateswith'another channel 1li which, through a recess or'port V15 in a cylinder cap 16, communicates withtheright end or" the cylinder 53. The channel 12 alsointersects and communicates with'the previously described channel 49 inbase I0 and thereby'the Vchannel ifi in cap 33.

It will be apparent .that when valve iii is manipulated to direct compressed air'into channel '12, a portion of such V4air will :flow through the interiorof'tube'Si and-into the portion A of the chamber 23 thereby causing the clamping bar IG to be elevated. Simultaneously, another portionof the air will iiow through channel into cylinder 53 and-causepiston rod 5l" to be displaced to the left, as viewed in Fig. 3. This movement of the piston causes the'camming rods El to engage an inclined surface `"i1 which is pro-- vided on the guderods Etyand cam these guide rods vandthe clamping block 'il into locking en gagement with the work-piece Awhich is to be clamped i against the top-plate 12.

The channel 13 communicates with a'port it in the end of the'cy1inderf3, as 'shown in Fig. 3. When the valve 1li vis manipulated'to direct `the air flow into channel 13," the air acts upon the Howeveryinasmuchas there is no air iiow intov 'the clamping bar chamber B, there .will be no poses ai-previduslyaclosed:cylindere port" 19. which communicateswithfthe; channel.r 148.; A-.zportion ofjgtheaain thuspescapes from Ycylinder .53 and travels through channel 43 in cap 33 into theLan- 11111.21', y:nassagewayg` 4| fini the stempfz'lfi "The .air

then` isi-directed throughiradial :opening Y1l2 finto the fportionfffofvthe :cavity 23xandfthus .causes clampingfbarifl Gzto; be retracted.

During the downward movement of the clamping bar, kthe entrapped' air in the chamber A is exhausted through the valve lll. The entrapped air -between plug "2 Il and cap' '33 is vented through an opening Vlljwhiclfi isrprovided in cap 33.

From the foregoing description it will be. apparentthat I have providedia clamping `device in which I obtainthe equalized"mechanical` lock ing' action'off two cammingro'ds througlithe .utilization of only-ay singlel actuating piston; thereby eiecting substantial economies in manufacture over the form of clamping device in which each camming rod is actuated by a separate fluid motor.

It will also be noted that this form of clamping device is so arranged that the mechanical locking means is retracted before the air is permitted to effect retraction of the clamping bar. This feature of the invention lends versatility to the operation of the clamping device and reduces the wear on the camming surfaces. By suitable manipulation of the valve 10, this sequential operation can be controlled to permit the workpiece to be adjusted in the device without completely releasing it from clamped position. For example, when the work-piece has been clamped and locked in position in the device it may be found necessary to make a slight adjustment in its position. By opening the valve 10- to cause retraction of the camming rods and then closing the valve before the piston 55 has moved back far enough to expose port 19, the clamping bar is thereby unlocked but not retracted. Its clamping pressure is reduced sufficiently however, to permit the position of the work-piece to be adjusted. After the necessary adjustment has been effected, the work-piece is still clamped by the bar I6 and the valve 'lll can be moved to cause the camming rods to advance thereby again locking the clamping bar against downward movement.

If there should be more wear on one pair of camming surface 62-11 than on the other pair, the rocker bar 65 will pivot to a limited extent to equalize the forward movement of the rods 6| so that they both engage the guide rods 6B simultaneously. Thus the rocker bar automatically compensates for unequal wear on the carnming surfaces.

Referring now to the form of the invention shown in Figs. 7 and 8, I have vshown a clamping device which embodies substantially all the features of the device shown in Figs. 1-6 but which is so arranged that there will be no delayed retraction of the clamping bar.

The base I of the modified form of device has the same channel arrangement for advancing and locking the clamping bar l as the form shown in Figs. 1-6. However, for purposes of retracting the camming rods 6l and the clamping bar I6, the channel 13 communicates directly with the channel 48 as well as with the cylinder port 18. The port 19 is eliminated in this form of the invention. Therefore when air flows intochannel 'I3 it acts upon the clamping bar Is and the pistonffisimultaneoisly, causing 4'concurrentTre'- traction'fofathese'elements;' j'

ii1It istosbe-iun'derstod that the 'forms lof my invention,-'herewithfshown and described, are to betaken asipreferred examples of the same, and

thatrvarious changes in' the shape, size and arrangement of :parts mayfbe resortedv to, without departing-'from the fspirit'of .my invention or the scope of the subjoined claims.

Having thus described my invention, I claim:

l. vIn a clamping device actuated by fluid pressure-fthe combination of ai cylinder, apiston slidablyrmounted in said. cylinder, 'a plurality: of slidably mounted cammingv rods" disposed in radially spaced relationship toY saidv piston, Ameans extending"transversely'ofsaid piston for 'securing==said camming'irodsto 'said piston for con'- current colinear lmovement therewith.'A a clampingibar, andfa-'camlfollower on said clamping bar engageableibyfsaid camming Yrodsto elevate said clamping bar in response to actuation of said piston.

2. In a clamping device actuated by uid pressure, the combination of a cylinder, a piston slidably mounted in said cylinder, a plurality of slid ably mounted camming rods disposed in radially spaced relationship to said piston, a unitary tie bar pivotally secured to said piston and said camming rods transversely thereof to effect concurrent colinear movement of said rods and said piston, a clamping bar, and a cam follower on said clamping bar engageable by said camming rods to elevate said clamping bar in response to actuation of said piston, said tie bar being pivotally movable in response to unequal engagement of said camming rods with said cam follower.

3. In a clamping device actuated by uicl pressure, the combination of a cylinder, a piston slidably mounted in said cylinder for movement in a horizontal datum plane, a plurality of slidably mounted camming rods disposed in radially spaced relationship to said piston, means for securing said camming rods to said piston for concurrent colinear movement therewith, a clamping bar mounted for movement in a vertical plane. control means for selectively directing fluid under pressure against said piston and against said clamping bar to elevate said bar toward clamping position, and a cam follower on said clamping bar engageable by said camming rods in response to actuation of said piston to mechanically further elevate and maintain said clamping bar in clamp ing position.

4. In a clamping device actuated by fluid pressure, the combination of a cylinder, a piston slidably mounted in said cylinder for movement in a, horizontal datum plane, a plurality of slidably mounted camming rods, a unitary tie bar pivotally secured to said piston and said camming rods to effect concurrent movement of said rods and said piston, a clamping bar mounted for movement in a vertical plane, control means for selectively directing fluid under pressure against said piston and against said clamping bar to elevate said clamping bar to clamping position, and a cam follower on said clamping bar engageable by said camming rods in response to actuation of said piston to mechanically secure said clamping bar in clamping position, said tie bar being pivotally movable in response to unequal engagement of said rods with said cam follower.

5. In a clamping deviceactuated by fluid pressure, the combination of a cylinder, a clamping bar slidably mounted in said cylinder for pressuresresponsive reciprocablemovement L'therein, a pressure-actuated cammingirodmovableiinto elevating engagement with Vsaid clamping bar when said clamping barl isfnearclamping position, meansfor directing fluid under'pressure against said camming rod to retract the same, and means responsive to continued retraction of said camming rod for directing fluid under pressure against said clampingv bar to retract the same.

6. In a clamping device actuated by fluid pressure, the combination of a cylinder, a clamping bar slidably mounted in said cylinder` for pressure-responsive reciprocable movement therein, a second cylinder, a .piston .sldably mounted in saidV second cylinder, camming rods secured to said piston in radially spaced relationship thereto and colinearly movable therewith, control means for selectively directing fluid under pressure into-said cylinders toelevate said clamping 20 bar toward clampingipositionand to advance said rods into elevating engagement With said clamping bar, and Ymeans responsive solely to prior retraction of said piston for directing uid under pressure againstA said clamping bar to retract the same.

7. A combination as dened in claim 6; including a unitary tie bar linking said camming rods and said piston, said tie bar being pivotally movable in response to unequal engagement of said rods with said clamping bar.

JOSEPH VERDERBER.

r'Refemnces Cited in the file of this patent UNITED 'STATES PATENTS- Number Name Date 2,130,618 Gnavi Sept. 20, 1938 2,260,662 .Farrell Oct. 28, 1941 2,443,775 Olson June 22, 1948 

